Telephone set.



C. S. BAKER.

TELEPHONE SET.

APPLICATION FILED SEPT. 6, |912.

2V-IGZ Patented Aug. 1, 1916.

` f, l 'IIIIIIIIIIIIIIiE-f WWI/mw@ 9 gm CHARLES SAUNDERS BAKER, OF PHILADELPHIA, PENNSYLVANIA.

TELEPHONE SET.

Specification of Letters atent.

Imatented Aug. 1, 1916.

Application filed September 6, 1912. Serial No. 718,844. Y

To all whom it may concern Be it known that I, CHARLES SAUNDERS BAKER, of Philadelphia, in the county of `Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Telephone Sets, whereof the following is a specification, reference being had to the accompanying drawings.

An object of my invention is to provide a telephone instrument in which the metallic casing and other exposed parts, are entirely eliminated from electrical connection with the telephone circuit. Heretofore it has been customary to use the metallic casing of telephone instruments to constitute one side of the telephone circuit, and the users of these instruments were liable to shocks resulting from accidentally crossed wires or other abnormal conditions of the circuit.

Another object of my invention is to prevent cross-connection between instruments of different systems which has heretofore been possible with the metallic casing interposed in the telephone circuits.

With these ends in view, rI have constructned a telephone in which the casing of the instrument forms no part of the circuit, and in which the moving metallic parts operating in conjunction with the receiver hook are mounted upon insulating material, and the switch for connecting the vinstrument to the line consists of a spring tongue which is insulated from the casing, and operated by the movement of a co-acting roller formed of insulating material moving with the receiver hook.

In the accompanying drawings, Figure I, is a view of a desk telephone partly in elevation and partly in section and with the transmitter removed. Fig. II, is an inverted .plan view of the telephone base, showing the induction coil and the method of its connections. Fig. III, is a back face view of the transmitter. Fig. IV, is a cross section through the transmitter as indicated at IV, IV, in Fig. III. Fig. V, is a partial vertical sectional view on the line V, V, of Fig. I. Fig. VI, is a detail showing the method of insulating one of the terminals of the phone.

In the said drawings, 1, designates the usual hollow metallic stem of the telephone which is clamped between the neck piece 2, and the base 3, by means of a central screw 5, engaging a lug 6, extending laterally from a vertical supporting plate 7, which is secured at its upper end to the neck piece 2, and supports the movable parts of the instrument.

rEhe hook 8, for the receiver, is fulcrumed on a screw 10, in the plate 7, and its downward motion is limited by means of a stop pin 11. To the plate 7, are secured two blocks 12, and 25, of insulating material by means of which the working parts of the instrument are insulated from the telephone circuit. 'Ihe insulating block 12, serves as a guide for a slide rod 15, which is pivoted at its upper end, to the arm of the receivery hook 8, and at its lower end carries a roller 16, also constructed of insulating material. A. spiral spring 17, encircles the slide rod 15, and operates to raise the hook when the receiver is removed.

' A metallic spring tongue 20, is secured at its upper vend to the insulating block 12, and its lower end is bent to form a cam face 21, which is adapted to co-act with the roller 16. lVVhen the receiver is removed from the hook it will readily be seen, (Fig. V), that the upward movement of the rod 15, will cause its roller 16, to be disengaged from the spring tongue 20, to a sufficient extent to permit the contact 22, carried at the lower end of the said tongue, to be forced against a similar contact 23, on a pin 24, secured in the insulating block 25. rIhe pin 24, projects through an insulating bushing 26, in the top plate of the base 3, and its lower end contacts with a spring piece 27, secured to one of the insulating bars 28, by which the induction coil 29, is secured to the base of the telephone. The spring piece 27, is connected by means of a screw 30, to one of the terminals of the secondary winding of the induction coil.

The insulation block 25, carries a second pin 31, which projects through an insulating bushing 32, in the base 3, and contacts with a spring piece 33, secured by means of a screw 35, to a depending lug 36, cast integral with the base 3. rIhe spring piece 33, is insulated from the base 3, by means of rubber washers 37, as clearly shown in Fig. VI, and carries a binding screw 38, to which is secured a cord 39, which together with a cord 40, connected by means of a nipple 41, to one of the terminals of the primary winding of the induction coil, passes through an insulating bushing 45, in the base 3, and is connected to the telephone line.

Referring now more particularly to Figs. III, and IV, the transmitter 50, is provided with a bridge piece 5l, for supporting the transmitter terminals and the carbon cup 4r, having an interposed liber insulating Washer 49. rlhe diaphragm'52, which is insulated by means of a mica washer 54, from the transmitter casing, is connected by means of a conductor 53, with a plate 55, secured to the bridge piece by means of screws 56, and 57, but insulated therefrom by the interposition of rubber gusset pieces 5S. Screw 57, is connected as indicated by the dotted line 60, with the insulated conductor 6l, which after passing through the neck and stem of Ythe instrument is soldered to the pin 3l,

already described. rlhe other terminal for the transmitter is insulated from the casing by means of. a block 62, and its terminal screw 63, is connected as indicated by the dotted line 65, with the insulated conductor 66, which after passing through the stem of the instrument, is soldered to the upper end of the Contact spring.

lt is not deemed necessary to further describe in detail the connections of the instrument as l otherwise employ the method well known in the art, but the connections within the instrument constructed according to my invention are such as to entirely eliminate the metallic casing from the telephone circuit.

lt is obvious that minor changes may be made in the arrangement without departing from the spirit of my invention.V

Having thus described my invention, I claim:

l. A telephone set comprising a base, a neck piece, a hollow stem disposed between the base and the neck piece, an insulating plate mounted in said hollow stem and connecting said neck piece to said base, a receiver hook pivoted on said plate, a resilient contact member supported by said plate, a fixed contact member supported by said plate, a rod connected to said receiver hook and movable longitudinally in said hollow stem, said rod being supported by said plate, a roller carried by said rod and adapted to coperate with said resilient contact member to alternately make and break the contact between said members upon movement of said hook.

2. A telephone set comprising a base, a neck piece, a hollow stem disposed between the base and the neck piece, an insulating plate mounted in said hollow stem and connecting' said neck piece to said base, a receiver hook pivoted on said plate, a resilient contact member supported by said plate, a iiXed contact member supported by said plate, an insulating block secured to said plate and having an opening therethrough, a rod connected with the receiver hook and extending thnough said insulating block,

said rod being movable longitudinally in said block and in said hollow stem, and means carried by the lower end of said rod and adapted to coperate with the resilient contact member to alternately make and break the contact between said members upon movement of said hook.

ln testimony whereof, l have hereunto signed my name at Philadelphia, Pennsylvania, this twenty-ninth day of August, 1912.

CHARLES SAUNDERS BAKER Witnesses:

JAMES H. BELL, E. L.l FULLERTON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

